Elevated birth defects in racial or ethnic minority children of women living near hazardous waste sites

This case-control study evaluated the relationship between birth defects in racial or ethnic minority children born during 1983-1988 and the potential exposure of their mothers to contaminants at hazardous waste sites in California. Four categories of race or ethnicity were used: black/African American, Hispanic/Latino, American Indian/Alaska Native, and Asian/Pacific Islander. Case subjects were 13,938 minority infants with major structural birth defects (identified by the California Birth Defects Monitoring Program) whose mothers resided in selected counties at the time of delivery. The control group was composed of 14,463 minority infants without birth defects who were randomly selected from the same birth cohort as the case subjects. The potential for exposure was determined by whether the mother resided at the time of delivery in the same census tract as a hazardous waste site that was on the U.S. Environmental Protection Agency's National Priorities List (NPL). Racial/ethnic minority infants whose mothers had been potentially exposed to hazardous waste were at slightly increased risk for birth defects (odds ratio [OR]=1.12, 95% confidence interval [CI]=0.98-1.27) than were racial/ethnic minority infants whose mothers had not been potentially exposed. The greatest association was between potential exposure and neural tube defects (OR=1.54, 95% CI=0.93-2.55), particularly anencephaly (OR=1.85, 95% CI=0.91-3.75). The strongest association between birth defects and potential exposure was among American Indians/Alaska Natives (OR=1.19, 95% CI=0.62-2.27). Despite the limitations of this study, the consistency of these findings with previous studies suggests an association between environmental risk factors and birth defects. This is particularly relevant to minority populations. We recommend further investigation of birth defects among minority communities, particularly among American Indians/Alaska Natives. Special attention should also be paid to those defects and contaminants that consistently are associated with exposure to hazardous waste.